"Undo + Save" doesn't save correctly

[The following applies to both FLACs and MP3s. WAVs are immune to this issue.]

🐛 The following steps seem to produce a bug that could land someone in hot water.
1) Open an audio file. For this example, the original is a 30-minute audio file called "Audio-30.flac"

2) Delete half of it
3) Save the new version as "Audio-15.flac"
4) Undo the deletion, so that the original length is restored.

5) Save this latest version under its original title "Audio-30.flac"
6) Close the audio file
7) Open the audio file to discover that the "undo" didn't save and your last 15 minutes are poof, gone. It's only a 15-minute audio file, not a 30.

Thankfully, I have so-far avoided this issue with numerous backups, but it's still seems to be a bug.

Thank you in advance for looking into this issue,
~ Matthew